TRACE MOISTURE MEASUREMENT IN HIGH PURITY AMMONIA GAS USING CAVITY RING-DOWN SPECTROSCOPY

摘要

Cavity Ring-Down Spectroscopy is now used for ultra-high-sensitive moisture measurements not only in inert and passive host gases, but also in some specialty gases that are corrosive and spectrally interfering. A lower detection limit of ~8 ppb for moisture in an ammonia carrier gas is reported by probing the 1392.53 nm near-infrared absorption line of the water molecule.